March 19, 1999

A large clinical trial of mechanical ventilator use for intensive care patients with acute respiratory distress syndrome (ARDS) has been stopped early so that critical care specialists around the country can be alerted to the study's successful results. As the study's coordinating center, the MGH supervised the conduct of the study, collecting and analyzing data from the 24 hospitals around the country that participated.

According to David Schoenfeld, PhD, of the MGH Biostatistics Center and principal investigator for the coordinating center, the decision to end the study was based on data gathered from the first 800 patients, which showed approximately 25 percent fewer deaths among patients receiving small, rather than large, breaths of air from a mechanical ventilator. A mechanical ventilator delivers breaths of oxygen-enriched air to a patient's body and removes breaths of carbon dioxide.

ARDS is an often fatal, inflammatory lung condition that usually occurs in conjunction with medical conditions, such as pneumonia, shock and trauma. Approximately 150,000 Americans are affected each year, and more than 40 percent die.

No specific therapies currently exist for these patients. Treatment involves supportive care in an intensive care unit, including use of a mechanical ventilator and supplemental oxygen to help patients breathe.

"This is a breakthrough study," says B. Taylor Thompson, MD, a co-investigator for the coordinating center. "Clinicians around the world will change current practices significantly in response to these findings."

The ARDS study was designed to compare the safety and efficacy of two different methods of setting a mechanical ventilator. Patients were randomly assigned to receive either relatively large (12 ml/kg) or small (6 ml/kg) breaths of air from the ventilator. Earlier laboratory studies had suggested that small breaths from the ventilator might not remove sufficient carbon dioxide and that large breaths might damage lung tissue. Several small clinical trials had failed to show clearly which approach was better.

"We are very pleased with the results of this study," says Schoenfeld. "It is always gratifying to make an advance like this that can save so many lives."

The National Heart, Lung and Blood Institute ARDS Clinical Network, a consortium that includes 24 hospitals, developed the study. Schoenfeld says that the MGH was chosen as a coordinator of the study in 1994 after a competitive national search. Additional information on the ARDS Network and the ventilator management study can be found at www.hedwig.mgh.harvard.edu/ardsnet.

The MGH biostatistical staff in charge of coordinating the study are, seated from left, Gail Wenzlow, MSW, MPH; Francine Molay, MSW; and Ann Born. Standing from left, Douglas Hayden, MA; Marek Ancukiewicz, PhD; David Schoenfeld, PhD; B. Taylor Thompson, MD; and Ali Kazeroonian. Not shown are Nancy Ringwood, RN, BSN, and Carolyn Hintlian, MPH, MBA.